For some types of aircraft, including transport aircraft, high-lift capability is important, particularly for takeoff and landing requirements. Aircraft designs are typically limited to a maximum takeoff weight and an associated runway length. For a given runway length, higher lift levels permit larger aircraft weights. Equivalently, for a given aircraft weight, higher lift allows for a lower stall speed and a shorter runway. From an operational perspective, higher lift translates into access to a larger number of airports. Whether the requirement is for a higher aircraft weight or for shorter runways, superior high-lift capability is a key design objective of the aircraft manufacturers.
It is known that some types of aircraft employ wing-mounted turbofan (or turbojet) engines configured to impinge the exhaust flow from the wing-mounted engines upon portions of the wing surfaces in order to augment wing lift during low-speed operations. These high-lift (or lift-augmentation) systems may favorably impact short-field take-off and landing capabilities, and may substantially improve the economical and operational characteristics of both military and commercial aircraft. More specifically, from an operational perspective, shorter runways translate into access to a larger number of airports. In the context of military airplanes, an area of high priority is the ability to operate off remote and austere fields. Military transports with short runway capability are important for maximizing the global reach of the airlift force. With respect to commercial transports, the economical impact of high-lift systems can be substantial. For example, an increase in takeoff lift-to-drag ratio (L/D) results in an increase in payload or an increased range.
Although desirable results have been achieved using high-lift aircraft exhaust systems in accordance with the prior art, novel systems and methods that provide improved performance and reduced noise would have greater utility.